Initialisation

All processes initialise the coupling and, if required, retrieve a local communicator for the component model internal parallelisation.

• USE mod_prism_proto

  Module to be used by the component models.

• CALL prism_init_comp_proto (compid, model_name, ierror)
  • compid [INTEGER; OUT]: component model ID
  • model_name [CHARACTER*6; IN]: name of calling model (as in namcouple)
  • ierror [INTEGER; OUT]: returned error code.

  Routine called by all component model processes, which initialises the coupling.

• CALL prism_get_localcomm_proto (local_comm, ierror )
  • local_comm [INTEGER; OUT]: value of local communicator
  • ierror [INTEGER; OUT]: returned error code.

  For MPI1: routine called by all model processes to get the value of a local communicator to be used by the model for its internal parallelisation.

  In fact, with MPI1, all component models started in a pseudo-MPMD mode share automatically the same MPI_COMM_WORLD communicator. Another communicator has to be used for the internal parallelisation of each model. OASIS3 creates this model local communicator following a ``coloring scheme"; its value is returned as the first argument of prism_get_localcomm_proto routine.

  With MPI2, the communicator MPI_COMM_WORLD will be returned as local communicator.

  Besides that, the differences between using PSMILe with MPI1 or MPI2 message passing are

  • The $CHANNEL in the namcouple; see section 5.2.
  • The way the models are started. With MPI2, only OASIS3 needs to be started at the command line; it will then spawn the component models at the beginning of the run. With MPI1, models have to be started by the user in a pseudo-MPMD mode; the way to do this depends on the computing platform. For more details, see section 8.3.